1. Field of the Invention
This invention relates to a resin composition for encapsulating a semiconductor chip and a semiconductor device therewith.
2. Description of the Related Art
Recently, epoxy resin compositions have been predominantly used for encapsulating a semiconductor chip because of their good balance among productivity, a cost and reliability. Along with reduction in a size and a thickness in a semiconductor device, an epoxy resin composition for encapsulating with a lower viscosity and higher strength has been needed. From such a situation, there has been recently a distinctive tendency to employing a less viscous resin and adding more inorganic fillers to an epoxy resin composition.
As a new trend, a semiconductor device has been more frequently mounted using an unleaded solder with a higher melting point than a conventional solder. For applying such a solder, a mounting temperature must be higher by about 20° C. than a conventional temperature, and thus a mounted semiconductor device becomes considerably less reliable than a device of the related art. Therefore, the need for improving reliability in a semiconductor device by providing a higher-level epoxy resin composition has increasingly become stronger, which further accelerates reducing a resin viscosity and increasing the amounts of inorganic fillers.
As well-known technique, a low viscosity and a high flowability during molding can be maintained by using a resin with a lower melt viscosity (see, Japanese Patent Application NO. 1995-130919 (pp. 2–5)) or by surface-processing inorganic fillers with a silane coupling agent for increasing the amounts of the inorganic fillers (see, Japanese Patent Application NO. 1996-20673 (pp. 2–4)).
However, any of these methods can meet only one of various needs and there have been no methods which are applicable to a wide range of applications by meeting all the needs. Since a melt viscosity during molding is insufficiently reduced according to any of the above methods, there has been needed more improved technique which can meet the requirements of the increased amounts of inorganic fillers and higher reliability without deterioration in flowability or curability.